Ball grid array systems for surface mounting an integrated circuit using a z-directed printed circuit board component

ABSTRACT

A printed circuit board according to one example embodiment includes a Z-directed component mounted in a mounting hole in the printed circuit board. The Z-directed component includes a body having a top surface, a bottom surface and a side surface. Four conductive channels extend through a portion of the body along the length of the body. The four conductive channels are spaced substantially equally around a perimeter of the body. An integrated circuit is mounted on a surface of the printed circuit board. The integrated circuit has a ball grid array that includes four conductive balls electrically connected to a corresponding one of the four conductive channels of the Z-directed component.

CROSS REFERENCES TO RELATED APPLICATIONS

This patent application is related to the following United States patentapplications, which are assigned to the assignee of the presentapplication: Ser. No. ______(Docket No. P246-US1), filed ______, 2012,entitled “Z-Directed Printed Circuit Board Components having ConductiveChannels for Controlling Transmission Line Impedance,” Ser. No. ______(Docket No. P246-US2), filed ______, 2012, entitled “Z-Directed PrintedCircuit Board Components having Different Dielectric Regions,” Ser. No.______ (Docket No. P246-US3), filed ______, 2012, entitled “Z-DirectedPrinted Circuit Board Components having Conductive Channels for ReducingRadiated Emissions,” and Ser. No. ______ (Docket No. P246-US5), filed______, 2012, entitled “Systems for Surface Mounting an IntegratedCircuit using a Z-Directed Printed Circuit Board Component.”

BACKGROUND

1. Field of the Disclosure

The present invention relates generally to electronic components andmore particularly to Z-directed electronic components for insertion intoa printed circuit board.

2. Description of the Related Art

The following co-pending United States patent applications, which areassigned to the assignee of the present application, describe various“Z-directed” components that are intended to be embedded or insertedinto a printed circuit board (“PCB”): Ser. No. 12/508,131 entitled“Z-Directed Components for Printed Circuit Boards,” Ser. No. 12/508,145entitled “Z-Directed Pass-Through Components for Printed CircuitBoards,” Ser. No. 12/508,158 entitled “Z-Directed Capacitor Componentsfor Printed Circuit Boards,” Ser. No. 12/508,188 entitled “Z-DirectedDelay Line Components for Printed Circuit Boards,” Ser. No. 12/508,199entitled “Z-Directed Filter Components for Printed Circuit Boards,” Ser.No. 12/508,204 entitled “Z-Directed Ferrite Bead Components for PrintedCircuit Boards,” Ser. No. 12/508,215 entitled “Z-Directed SwitchComponents for Printed Circuit Boards,” Ser. No. 12/508,236 entitled“Z-Directed Connector Components for Printed Circuit Boards,” and Ser.No. 12/508,248 entitled “Z-Directed Variable Value Components forPrinted Circuit Boards.”

Printed Circuit Board (PCB) manufacturing primarily uses two types ofcomponents. The first type is a pin through-hole part that uses metallicleads that are soldered into a plated through-hole in the PCB. Thesecond type is a surface mount part that sits on the surface of a PCBand is attached by soldering to pads on the surface. As densities ofcomponents for printed circuit boards have increased and higherfrequencies of operation are used, some circuits' designs have becomevery difficult to achieve. The Z-directed components described in theforegoing patent applications are designed to improve the componentdensities and frequencies of operation. The Z-directed components occupyless space on the surface of a PCB and for high frequency circuits, e.g.clock rates greater than 1 GHz, allow for higher frequency of operation.The foregoing patent applications describe various types of Z-directedcomponents including, but not limited to, capacitors, delay lines,transistors, switches, and connectors.

Transmission line impedance discontinuities are a problem in circuitsutilizing a high frequency signal. These discontinuities may causesignal attenuation and other parasitic effects. Accordingly, a componentthat provides a substantially constant transmission line impedance isoften desired. Another problem with high frequency circuits is thegeneration and receipt of electromagnetic interference (EMI). Asignificant source of EMI in a circuit is its loop area. A circuithaving a greater loop area may be more prone to pick up an unwantedsignal or radiate unwanted energy that may interfere with its operationor the operation of other circuits nearby. Accordingly, a componenthaving a minimal loop area is often desired.

SUMMARY

A printed circuit board according to one example embodiment includes aZ-directed component mounted in a mounting hole in the printed circuitboard. The Z-directed component includes a body having a top surface, abottom surface and a side surface. A portion of the body is composed ofan insulator. Four conductive channels extend through a portion of thebody along the length of the body. The four conductive channels arespaced substantially equally around a perimeter of the body. A first anda second of the four conductive channels are positioned opposite eachother and a third and a fourth of the four conductive channels arepositioned opposite each other. An integrated circuit is mounted on asurface of the printed circuit board. The integrated circuit has a ballgrid array that includes four conductive balls electrically connected toa corresponding one of the four conductive channels of the Z-directedcomponent. Four wire bonds electrically connect the four conductiveballs of the ball grid array to four corresponding contacts on theintegrated circuit. The first and second conductive channels of theZ-directed component are electrically connected to a common ground pathof the printed circuit board. The third conductive channel of theZ-directed component is electrically connected to a first voltage supplypath of the printed circuit board. The fourth conductive channel of theZ-directed component is electrically connected to a second voltagesupply path of the printed circuit board. A first of the four contactson the integrated circuit electrically connected to the first conductivechannel is positioned next to a third of the four contacts electricallyconnected to the third conductive channel. A second of the four contactselectrically connected to the second conductive channel is positionednext to a fourth of the four contacts electrically connected to thefourth conductive channel.

A printed circuit board according to one example embodiment includes aZ-directed capacitor mounted in a mounting hole in the printed circuitboard. The Z-directed capacitor includes a body having a top surface, abottom surface and a side surface. The body includes a plurality ofstacked layers composed of a dielectric material and having a conductivematerial plated on a surface thereof. Four conductive channels extendthrough a portion of the body along the length of the body. The fourconductive channels are selectively connected to the conductive materialplated on the surface of the stacked layers. An integrated circuit ismounted on a surface of the printed circuit board. The integratedcircuit has a ball grid array that includes four conductive balls eachbeing electrically connected to a corresponding one of the fourconductive channels of the Z-directed component. The integrated circuithas a core region having a first voltage supply path and a ground pathand an input/output region having a second voltage supply path and theground path. The second voltage supply path is configured to transmit avoltage different from a voltage transmitted by the first voltage supplypath. A first and a second of the four conductive channels of theZ-directed component are electrically connected to the ground path. Athird of the four conductive channels of the Z-directed component iselectrically connected to the first voltage supply path. A fourth of thefour conductive channels of the Z-directed component is electricallyconnected to the second voltage supply path.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned and other features and advantages of the variousembodiments, and the manner of attaining them, will become more apparentand will be better understood by reference to the accompanying drawings.

FIG. 1 is a perspective view of a Z-directed component according to oneexample embodiment.

FIG. 2 is a transparent perspective view of the Z-directed componentshown in FIG. 1 illustrating the internal arrangement of elements of theZ-directed component.

FIGS. 3A-3F are perspective views showing various example shapes for thebody of a Z-directed component.

FIGS. 4A-4C are perspective views showing various example side channelconfigurations for a Z-directed component.

FIGS. 5A-5H are perspective views showing various example channelconfigurations for the body of a Z-directed component.

FIG. 6 is a schematic illustration of various example elements orelectronic components that may be provided within the body of aZ-directed component in series with a conductive channel.

FIG. 7 is a schematic cross-sectional view of a Z-directed componentflush mounted in a PCB showing conductive traces and connections to theZ-directed component according to one example embodiment.

FIG. 8 is a top plan view of the Z-directed component and PCB shown inFIG. 8.

FIG. 9 is a schematic cross-sectional view of a Z-directed componentflush mounted in a PCB showing ground loops for the Z-directed componentwith the Z-directed component further having a decoupling capacitorwithin its body according to one example embodiment.

FIG. 10 is a schematic cross-sectional view of a Z-directed componentflush mounted in a PCB showing a Z-directed component for transferring asignal trace from one internal layer of a PCB to another internal layerof that PCB according to one example embodiment.

FIG. 11 is a perspective view of a Z-directed capacitor havingvertically oriented conductive sheets according to one exampleembodiment.

FIG. 12 is an exploded view of a Z-directed capacitor having stackedlayers according to one example embodiment.

FIG. 13 is an exploded view of a Z-directed capacitor having stackedlayers and a pair of conductive channels next to a signal path throughthe component according to one example embodiment.

FIGS. 14A and 14B are plan views of a pair of support members of theZ-directed capacitor shown in FIG. 13.

FIG. 15 is a perspective view of a Z-directed capacitor havingvertically oriented conductive sheets and a pair of conductive channelsnext to a signal path through the component according to one exampleembodiment.

FIG. 16 is a perspective view of a Z-directed signal pass-throughcomponent having a pair of conductive channels next to a signal paththrough the component according to one example embodiment.

FIG. 17 is a perspective view of a Z-directed signal pass-throughcomponent having a pair of conductive channels next to a signal paththrough the component according to another example embodiment.

FIG. 18 is a perspective view of a Z-directed signal pass-throughcomponent having a differential signal according to one exampleembodiment.

FIG. 19 is a perspective view of a Z-directed capacitor comprised ofmultiple stacked layers having different dielectric constants accordingto one example embodiment.

FIG. 20 is a perspective view of a Z-directed capacitor havingvertically oriented conductive sheets and having a high dielectric outerregion and a low dielectric inner region according to one exampleembodiment.

FIG. 21 is a perspective view of a Z-directed delay line componentaccording to one example embodiment.

FIG. 22 is a perspective view of a Z-directed capacitor that includesfour plated side channels according to one example embodiment.

FIG. 23 is a perspective view of the Z-directed capacitor shown in FIG.22 mounted in a PCB and connected to a ball grid array of an integratedcircuit.

FIG. 24 is a schematic depiction of the current and magnetic elements ofthe Z-directed capacitor shown in FIGS. 22 and 23.

FIGS. 25A-D are plan views of various example embodiments of supportmembers for the Z-directed capacitor shown in FIGS. 22 and 23.

FIG. 26A is a top schematic view of a prior art integrated circuitmounted on a PCB via a ball grid array and connected to a pair ofsurface mounted capacitors.

FIG. 26B is a schematic diagram of the integrated circuit shown in FIG.26A.

FIG. 27A is a top schematic view of an integrated circuit mounted on aPCB via a ball grid array and connected to a Z-directed capacitoraccording to one example embodiment.

FIG. 27B is a schematic diagram of the integrated circuit shown in FIG.27A.

FIG. 28 is a perspective view of a Z-directed capacitor that includesfour plated side channels and a center conductive channel according toone example embodiment.

FIGS. 29A-D are plan views of various example embodiments of supportmembers for the Z-directed capacitor shown in FIG. 26.

FIG. 30 is a plan view of a top surface of a Z-directed componentmounted in a PCB and connected to four conductive ball pads according toone example embodiment.

FIG. 31 is a perspective view of the Z-directed component shown in FIG.28 connected to a ball grid array of an integrated circuit according toone example embodiment.

FIGS. 32A-E are plan views of various example embodiments of Z-directedcomponents connected to conductive ball pads for connecting to a ballgrid array.

FIG. 33A is a perspective view of a Z-directed component having a domeformed on an end thereof according to one example embodiment.

FIG. 33B is a perspective view of a Z-directed component having achamfered end according to one example embodiment.

FIG. 34A is a perspective view of a Z-directed component inserted into amounting hole in a PCB, the Z-directed component having a conductivestrip applied to a side surface thereof according to one exampleembodiment.

FIG. 34B is a side cutaway view of the Z-directed component and PCBshown in FIG. 32A.

DETAILED DESCRIPTION

The following description and drawings illustrate embodimentssufficiently to enable those skilled in the art to practice the presentinvention. It is to be understood that the disclosure is not limited tothe details of construction and the arrangement of components set forthin the following description or illustrated in the drawings. Theinvention is capable of other embodiments and of being practiced or ofbeing carried out in various ways. For example, other embodiments mayincorporate structural, chronological, electrical, process, and otherchanges. Examples merely typify possible variations. Individualcomponents and functions are optional unless explicitly required, andthe sequence of operations may vary. Portions and features of someembodiments may be included in or substituted for those of others. Thescope of the application encompasses the appended claims and allavailable equivalents. The following description is, therefore, not tobe taken in a limited sense and the scope of the present invention isdefined by the appended claims.

Also, it is to be understood that the phraseology and terminology usedherein is for the purpose of description and should not be regarded aslimiting. The use of “including,” “comprising,” or “having” andvariations thereof herein is meant to encompass the items listedthereafter and equivalents thereof as well as additional items. Unlesslimited otherwise, the terms “connected,” “coupled,” and “mounted,” andvariations thereof herein are used broadly and encompass direct andindirect connections, couplings, and mountings. In addition, the terms“connected” and “coupled” and variations thereof are not restricted tophysical or mechanical connections or couplings.

Overview of Z-Directed Components

An X-Y-Z frame of reference is used herein. The X and Y axes describethe plane defined by the face of a printed circuit board. The Z-axisdescribes a direction perpendicular to the plane of the circuit board.The top surface of the PCB has a zero Z-value. A component with anegative Z-direction value indicates that the component is inserted intothe top surface of the PCB. Such a component may be above (extend past),flush with, or recessed below either the top surface and/or the bottomsurface of the PCB. A component having both a positive and negativeZ-direction value indicates that the component is partially insertedinto the surface of the PCB. The Z-directed components are intended tobe inserted into a hole or recess in a printed circuit board. Dependingon the shape and length of the component(s), more than one Z-directedcomponent may be inserted into a single mounting hole in the PCB, suchas being stacked together or positioned side by side. The hole may be athrough-hole (a hole from the top surface through to the bottomsurface), a blind hole (an opening or recess through either the top orbottom surface into an interior portion or internal layer of the PCB) oran internal cavity such that the Z-directed component is embedded withinthe PCB.

For a PCB having conductive traces on both external layers, one externallayer is termed the top surface and the other the bottom surface. Whereonly one external layer has conductive traces, that external surface isreferred to as the top surface. The Z-directed component is referred toas having a top surface, a bottom surface and a side surface. Thereferences to top and bottom surfaces of the Z-directed componentconform to the convention used to refer to the top and bottom surfacesof the PCB. The side surface of a Z-directed component extends betweenthe top and bottom surfaces of the PCB and would be adjacent to the wallof the mounting hole in the PCB where the mounting hole is perpendicularto the face of the PCB. This use of top, bottom and side should not betaken as limiting how a Z-directed component may be mounted into a PCB.Although the components are described herein as being mounted in aZ-direction, this does not mean that such components are limited tobeing inserted into a PCB only along the Z-axis. Z-directed componentsmay be mounted normal to the plane of the PCB from the top or bottomsurfaces or both surfaces, mounted at an angle thereto or, depending onthe thickness of the PCB and the dimensions of the Z-directed component,inserted into the edge of the PCB between the top and bottom surfaces ofthe PCB. Further, the Z-directed components may be inserted into theedge of the PCB even if the Z-directed component is wider than the PCBis tall as long as the Z-directed component is held in place.

The Z-directed components may be made from various combinations ofmaterials commonly used in electronic components. The signal connectionpaths are made from conductors, which are materials that have highconductivity. Unless otherwise stated, reference to conductivity hereinrefers to electrical conductivity. Conducting materials include, but arenot limited to, copper, gold, aluminum, silver, tin, lead and manyothers. The Z-directed components may have areas that need to beinsulated from other areas by using insulator materials that have lowconductivity like plastic, glass, FR4 (epoxy & fiberglass), air, mica,ceramic and others. Capacitors are typically made of two conductingplates separated by an insulator material that has a high permittivity(dielectric constant). Permittivity is a parameter that shows theability to store electric fields in the materials like ceramic, mica,tantalum and others. A Z-directed component that is constructed as aresistor requires materials that have properties that are between aconductor and insulator having a finite amount of resistivity, which isthe reciprocal of conductivity. Materials like carbon, dopedsemiconductor, nichrome, tin-oxide and others are used for theirresistive properties. Inductors are typically made of coils of wires orconductors wrapped around a material with high permeability.Permeability is a parameter that shows the ability to store magneticfields in the material which may include iron and alloys likenickel-zinc, manganese-zinc, nickel-iron and others. Transistors such asfield effect transistors (“FETs”) are electronic devices that are madefrom semiconductors that behave in a nonlinear fashion and are made fromsilicon, germanium, gallium arsenide and others.

Throughout the application there are references that discuss differentmaterials, properties of materials or terminology interchangeably ascurrently used in the art of material science and electrical componentdesign. Because of the flexibility in how a Z-directed component may beemployed and the number of materials that may be used, it is alsocontemplated that Z-directed components may be constructed of materialsthat have not been discovered or created to date. The body of aZ-directed component will in general be comprised of an insulatormaterial unless otherwise called out in the description for a particulardesign of a Z-directed component. This material may possess a desiredpermittivity, e.g., the body of a capacitor will typically be comprisedof an insulator material having a relatively high dielectric constant.

PCBs using a Z-directed component may be constructed to have a singleconductive layer or multiple conductive layers as is known. The PCB mayhave conductive traces on the top surface only, on the bottom surfaceonly, or on both the top and bottom surfaces. In addition, one or moreintermediate internal conductive trace layers may also be present in thePCB.

Connections between a Z-directed component and the traces in or on a PCBmay be accomplished by soldering techniques, screening techniques,extruding techniques or plating techniques known in the art. Dependingon the application, solder pastes and conductive adhesives may be used.In some configurations, compressive conductive members may be used tointerconnect a Z-directed component to conductive traces found on thePCB.

The most general form of a Z-directed component comprises a body havinga top surface, a bottom surface and a side surface, a cross-sectionalshape that is insertable into a mounting hole of a given depth D withina PCB with a portion of the body comprising an insulator material. Allof the embodiments described herein for Z-directed components are basedon this general form.

For example, FIGS. 1 and 2 show an embodiment of a Z-directed component10. In this embodiment, Z-directed component 10 includes a generallycylindrical body 12 having a top surface 12 t, a bottom surface 12 b, aside surface 12 s, and a length L generally corresponding to the depth Dof the mounting hole. The length L can be less than, equal to or greaterthan the depth D. In the former two cases, Z-directed component 10 wouldin one case be below at least one of the top and bottom surfaces of thePCB and in the other it may be flush with the two surfaces of the PCB.Where length L is greater than depth D, Z-directed component 10 wouldnot be flush mounted with at least one of the top and bottom surfaces ofthe PCB. However, with this non-flush mount, Z-directed component 10would be capable of being used to interconnect to another component oranother PCB that is positioned nearby. The mounting hole is typically athrough-hole extending between the top and bottom surfaces of the PCBbut it may also be a blind hole. When recessed below the surface of thePCB, additional resist areas may be required in the hole of the PCB tokeep from plating the entire circumferential area around the hole.

Z-directed component 10 in one form may have at least one conductivechannel 14 extending through an interior portion of body 12 along itslength. Top and bottom conductive traces 16 t, 16 b are provided on thetop and bottom end surfaces 12 t, 12 b of body 12 that extend fromrespective ends of the conductive channel 14 to the edge of Z-directedcomponent 10. In this embodiment, body 12 comprises an insulatormaterial. Depending on its function, body 12 of Z-directed component 10may be made of a variety of materials having different properties. Theseproperties include being conductive, resistive, magnetic, dielectric, orsemi-conductive or various combinations of properties as describedherein. Examples of materials that have the properties are copper,carbon, iron, ceramic or silicon, respectively. Body 12 of Z-directedcomponent 10 may also comprise a number of different networks needed tooperate a circuit that will be discussed later.

One or more longitudinally extending channels or wells may be providedon the side surface of body 12 of Z-directed component 10. The channelmay extend from one of the top surface and the bottom surface of body 12toward the opposite surface. As illustrated, two concave side wells orchannels 18 and 20 are provided in the outer surface of Z-directedcomponent 10 extending the length of body 12. When plated or soldered,these channels allow electrical connections to be made to Z-directedcomponent 10, through the PCB, as well as to internal conductive layerswithin the PCB. The length of side channels 18 or 20 may extend lessthan the entire length of body 12.

FIG. 2 shows the same component as in FIG. 1 but with all the surfacestransparent. Conductive channel 14 is shown as a cylinder extendingthrough the center of Z-directed component 10. Other shapes may also beused for conductive channel 14. Traces 16 t and 16 b can be seenextending from ends 14 t and 14 b of conductive channel 14,respectively, to the edge of body 12. While traces 16 t and 16 b areshown as being in alignment with one another (zero degrees apart), thisis not a requirement and they may be positioned as needed for aparticular design. For example, traces 16 t and 16 b may be 180 degreesapart or 90 degrees apart or any other increment.

The shape of the body of the Z-directed component may be any shape thatcan fit into a mounting hole in a PCB. FIGS. 3A-3F illustrate possiblebody shapes for a Z-directed component. FIG. 3A shows a triangularcross-sectional body 40; FIG. 3B shows a rectangular cross-sectionalbody 42; FIG. 3C shows a frusto-conical body 44; FIG. 3D shows an ovatecross-sectional cylindrical body 46; and FIG. 3E shows a cylindricalbody 48. FIG. 3F shows a stepped cylindrical body 50 where one portion52 has a larger diameter than another portion 54. With this arrangement,the Z-directed component may be mounted on the surface of the PCB whilehaving a section inserted into a mounting hole provided in the PCB. Theedges of the Z-directed component may be beveled to help with aligningthe Z-directed component for insertion into a mounting hole in a PCB.Other shapes and combinations of those illustrated may also be used fora Z-directed component as desired.

For a Z-directed component, the channels for plating can be of variouscross-sectional shapes and lengths. The only requirement is that platingor solder material make the proper connections to the Z-directedcomponent and corresponding conductive traces in or on the PCB. Sidechannels 18 or 20 may have, for example, V-, C- or U-shapedcross-sections, semi-circular or elliptical cross-sections. Where morethan one channel is provided, each channel may have the same or adifferent cross-sectional shape. FIGS. 4A-4C illustrate three sidechannel shapes. In FIG. 4A, V-shaped side channels 60 are shown. In FIG.4B, U-shaped side channels 62 are shown. In FIG. 4C, wavy or irregularcross-sectional side channel shapes 65 are shown. FIGS. 1 and 2 showC-shaped cross-sectional side channels 18, 20.

The numbers of layers in a PCB may vary from being single sided to beingover 22 layers and may have different overall thicknesses that rangefrom less than 0.051 inch to over 0.093 inch or more, or in onepreferred embodiment between about 0.051 and about 0.093. Where a flushmount is desired, the length of the Z-directed component will depend onthe thickness of the PCB into which it is intended to be inserted. TheZ-directed component's length may also vary depending on the intendedfunction and tolerance of a process. The preferred lengths will be wherethe Z-directed component is either flush with the surfaces or extendsslightly beyond the surface of the PCB. This would keep the platingsolution from plating completely around the interior of the PCB holethat may cause a short in some cases. It is possible to add a resistmaterial around the interior of a PCB hole to only allow plating in thedesired areas. However, there are some cases where it is desired tocompletely plate around the interior of a PCB hole above and below theZ-directed component. For example, if the top layer of the PCB is asupply voltage (V_(CC)) plane and the bottom layer is a ground voltage(GND) plane then a decoupling capacitor would have lower impedance ifthe connection used a greater volume of copper to make the connection.

There are a number of features that can be added to a Z-directedcomponent to create different mechanical and electrical characteristics.The number of channels or conductors can be varied from zero to anynumber that can maintain enough strength to take the stresses ofinsertion, plating, manufacturing processes and operation of the PCB inits intended environment. The outer surface of a Z-directed componentmay have a coating that glues it in place. Flanges or radial projectionsmay also be used to prevent over or under insertion of a Z-directedcomponent into the mounting hole, particularly where the mounting holeis a through-hole. A surface coating material may also be used topromote or impede migration of the plating or solder material. Variouslocating or orienting features may be provided such as a recess orprojection, or a visual or magnetic indicator on an end surface of theZ-directed component. Further, a connecting feature such as a conductivepad, a spring loaded style pogo-pin or even a simple spring may beincluded to add an additional electrical connection (such as frameground) point to a PCB.

A Z-directed component may take on several roles depending on the numberof ports or terminals needed to make connections to the PCB. Somepossibilities are shown in FIGS. 5A-H. FIG. 5A is a Z-directed componentconfigured as 0-port device 70A used as a plug so that if a filter or acomponent is optional then the plug stops the hole from being plated.After the PCB has been manufactured, the 0-port device 70A may beremoved and another Z-directed component may be inserted, plated andconnected to the circuit. FIGS. 5B-5H illustrate various configurationsuseful for multi-terminal devices such as resistors, diodes,transistors, and/or clock circuits. FIG. 5B shows a 1-port or singlesignal Z-directed component 70B having a conductive channel 71 through acenter portion of the component connected to top and bottom conductivetraces 72 t, 72 b. FIG. 5C shows a 1-port 1-channel Z-directed component70C where one plated side well or channel 73 is provided in addition toconductive channel 71 through the component, which is connected to topand bottom conductive traces 72 t and 72 b. FIG. 5D shows a Z-directedcomponent 70D having two side wells 73 and 75 in addition to conductivechannel 71 through the component which is connected to top and bottomtraces 72 t, 72 b. The Z-directed component 70E of FIG. 5E has threeside wells 73, 75 and 76 in addition to conductive channel 71 throughthe component, which is connected to top and bottom traces 72 t, 72 b.FIG. 5F shows Z-directed component 70F having two conductive channels 71and 77 through the component each with their respective top and bottomtraces 72 t, 72 b and 78 t, 78 b and no side channels or wells.Z-directed component 70F is a two signal device to be primarily used fordifferential signaling. FIG. 5G shows a Z-directed component 70G havingone side well 73 and two conductive channels 71 and 77 each with theirrespective top and bottom traces 72 t, 72 b and 78 t, 78 b. FIG. 5Hshows Z-directed component 70H having one conductive channel 71 with topand bottom traces 72 t, 72 b and a blind well or partial well 78extending from the top surface along a portion of the side surface thatwill allow the plating material or solder to stop at a given depth. Forone skilled in the art, the number of wells and signals is only limitedby the space, required well or channel sizes.

The various embodiments and features discussed for a Z-directedcomponent are meant to be illustrative and not limiting. A Z-directedcomponent may be made of a bulk material that performs a networkfunction or may have other parts embedded into its body. A Z-directedcomponent may be a multi-terminal device and, therefore, may be used toperform a variety of functions including, but not limited to:transmission lines, delay lines, T filters, decoupling capacitors,inductors, common mode chokes, resistors, differential pair passthroughs, differential ferrite beads, diodes, or ESD protection devices(varistors). Combinations of these functions may be provided within onecomponent.

FIG. 6 illustrates various example configurations for a conductivechannel in a Z-directed component. As shown, channel 90 has a region 92intermediate the ends comprising a material having properties such asconductive, resistive, magnetic, dielectric, capacitive, semi-conductiveproperties or combinations thereof. These materials form a variety ofcomponents. Additionally, one or more components may be inserted orembedded into region 92 with portions of the conductive channelextending from the terminals of the component. A capacitor 92 a may beprovided in region 92. Similarly, a diode 92 b, a transistor 92 c suchas a MOSFET 92 d, a zener diode 92 e, an inductor 92 f, a surgesuppressor 92 g, a resistor 92 h, a diac 92 i, a varactor 92 j andcombinations of these items are further examples of materials that maybe provided in region 92 of conductive channel 90. While region 92 isshown as being centered within the conductive channel 90, it is notlimited to that location.

For a multi-terminal device such as transistor 92 c, MOSFET 92 d, anintegrated circuit 92 k, or a transformer 92 l, one portion of theconductive channel may be between the top surface trace and a firstterminal of the device and the other portion of the conductive channelbetween the bottom surface trace and a second terminal of the device.For additional device terminals, additional conductors may be providedin the body of the Z-directed component to allow electrical connectionto the remaining terminals or additional conductive traces may beprovided within the body of the Z-directed component between theadditional terminals and channels on the side surface of the body of aZ-directed component allowing electrical connection to an externalconductive trace. Various connection configurations to a multipleterminal device may be used in a Z-directed component.

Accordingly, those skilled in the art will appreciate that various typesof Z-directed components may be utilized including, but not limited to,capacitors, delay lines, transistors, switches, and connectors. Forexample, FIGS. 7 and 8 illustrate a Z-directed component termed a signalpass-through that is used for passing a signal trace from the topsurface of a PCB to the bottom surface.

FIG. 7 shows a sectional view taken along line 7-7 in FIG. 8 of a PCB200 having four conductive planes or layers comprising, from top tobottom, a ground (GND) plane or trace 202, a voltage supply plane(V_(CC)) 204, a second ground (GND) plane 206 and a third ground (GND)plane or trace 208 separated by nonconductive material such as aphenolic plastic, such as FR4, which is widely used as is known in theart. PCB 200 may be used for high frequency signals. The top and bottomground planes or traces 202 and 208, respectively, on the top and bottomsurfaces 212 and 214, respectively, of PCB 200 are connected toconductive traces leading up to Z-directed component 220. A mountinghole 216 having a depth D in a negative Z direction is provided in PCB200 for the flush mounting of Z-directed component 220. Here depth Dcorresponds to the thickness of PCB 200; however, depth D may be lessthan the thickness of PCB 200 creating a blind hole therein. Mountinghole 216, as illustrated, is a through-hole that is round incross-section to accommodate Z-directed component 220 but may have crosssections to accommodate the insertion of Z-directed components havingother body configurations. In other words, mounting holes are sized sothat Z-directed components are insertable therein. For example, aZ-directed component having a cylindrical shape may be inserted into asquare mounting hole and vice versa. In the cases where the Z-directedcomponent does not make a tight fit, resist materials will have to beadded to the areas of the component and PCB where copper plating is notdesired.

Z-directed component 220 is illustrated as a three lead component thatis flush mounted with respect to both the top surface 212 and bottomsurface 214 of PCB 200. Z-directed component 220 is illustrated ashaving a generally cylindrical body 222 of a length L. A centerconductive channel or lead 224, illustrated as being cylindrical, isshown extending the length of body 222. Two concave side wells orchannels 226 and 228, which define the other two leads, are provided onthe side surface of Z-directed component 220 extending the length ofbody 222. Side channels 226 and 228 are plated for making electricalconnections to Z-directed component 220 from various layers of PCB 200.As shown, the ground plane traces on layers 202, 206, and 208 of PCB 100are electrically connected to side channels 226 and 228. V_(CC) plane204 does not connect to Z-directed component 220 as shown by the gap 219between V_(CC) plane 204 and wall 217 of mounting hole 216.

FIG. 8 illustrates a top view of Z-directed component 220 in PCB 200.Three conductive traces 250, 252 and 254 lead up to the edge of wall 217of mounting hole 216. As illustrated, trace 252 serves as ahigh-frequency signal trace to be passed from the top surface 212 to thebottom surface 214 of PCB 200 via Z-directed component 220. Conductivetraces 250 and 254 serve as ground nets. Center lead or conductivechannel 224 is electrically connected to trace 252 on the top surface212 of PCB 200 by a top trace 245 and plating bridge 230. Top trace 245on the top surface of Z-directed component 220 extends from the top end224 t of conductive channel 224 to the edge of Z-directed component 220.Although not shown, the bottom side of Z-directed component 220 andbottom surface 214 of PCB 200 is configured in a similar arrangement oftraces as shown on top surface 212 of PCB 200 illustrated in FIG. 8. Abottom trace on the bottom surface of Z-directed component 220 extendsfrom the bottom of conductive channel 224 to the edge of Z-directedcomponent 220. A plating bridge is used to make the electricalconnection between the bottom trace and another high frequency signaltrace provided on the bottom surface of PCB 200. The transmission lineimpedance of the Z-directed component can be adjusted to match the PCBtrace impedance by controlling the conductor sizes and distances betweeneach conductor which improves the high speed performance of the PCB. Forexample, each of the electrical paths formed by the Z-directed componentshown in FIG. 8, e.g., the electrical path formed by conductor 244,trace 245, and trace 252, has a substantially uniform width in order tocontrol the transmission line impedance through the path (see also FIGS.1 and 2).

During the plating process, wells 256 and 258 formed between wall 217 ofmounting hole 216 and side channels 226 and 228 allow plating materialor solder to pass from the top surface 212 to the bottom surface 214electrically interconnecting traces 250 and 254, respectively, to sidechannels 226 and 228, respectively, of Z-directed component 220 and alsoto similarly situated traces provided on the bottom surface 214 of PCB200 interconnecting ground planes or traces 202, 206 and 208. Theplating is not shown for purposes of illustrating the structure. In thisembodiment, V_(CC) plane 204 does not connect to Z-directed component220.

One of the challenges for high frequency signal speeds is thereflections and discontinuities due to signal trace transmission lineimpedance changes. Many PCB layouts try to keep high frequency signalson one layer because of these discontinuities caused by the routing ofsignal traces through the PCB. Standard vias through a PCB have to bespaced some distance apart which creates high impedance between thesignal via and the return signal via or ground via. As illustrated inFIGS. 7 and 8, the Z-directed component and the return ground or signalshave a very close and controlled proximity that allow more constantimpedance from the top surface 212 to the bottom surface 214 of PCB 200.

A Z-directed signal pass through component may also comprise adecoupling capacitor that will allow the reference plane of a signal toswitch from a ground plane, designated GND, to a voltage supply plane,designated V_(CC), without having a high frequency discontinuity. FIG. 9shows a cross-sectional view of a typical 4-layer PCB 300 with a signaltrace 302 transferring between the top layer 304 and the bottom layer306. Z-directed component 310, similar to that shown in FIG. 5D, havingbody 312 connects signal trace 302 through center conductive channel314. Z-directed component 310 also comprises plated side channels 316and 318 extending along the side surface 312 s of the body 312. The top314 t and bottom 314 b of conductive channel 314 are connected toconductive traces 318 t and 318 b on the top 312 t and bottom 312 b ofbody 312. These, in turn, are connected to signal trace 302 via top andbottom plating bridges 330 t and 330 b. Side channels 316 and 318 areplated to GND plane 332 and V_(CC) plane 334, respectively. Connectionpoints 336 and 338, respectively, illustrate this electrical connection.Schematically illustrated decoupling capacitor 350 is internal to body312 and is connected between side channels 316 and 318. Decouplingcapacitor 350 may be a separate capacitor integrated into the body 312of Z-directed component 310 or it can be formed by fabricating a portionof the body 312 of Z-directed component 310 from the required materialswith dielectric properties between conductive surfaces.

The path for signal trace 302 is illustrated with diagonal hatching andcan be seen to run from top layer 304 to bottom layer 306. GND plane 332and side channel 316 are electrically connected at 336 with the signalpath return indicated by the dark stippling 362. V_(CC) plane 334 andside channel 318 are electrically connected at 338 with the signal pathreturn indicated by the light stippling 364. As is known in the art,where a signal plane or trace is not to be connected to the insertedpart, those portions are spaced apart from the component as shown at370. Where a signal plane or trace is to be connected to an insertedcomponent, the signal plane or trace is provided at the wall or edge ofthe opening to allow the plating material or solder to bridgetherebetween as illustrated at points 330 t, 330 b, 336, and 338.

The vertically hatched portion 380 shows the high speed loop areabetween the signal trace and return current path described by the signaltrace 302 and the GND plane 332 or V_(CC) plane 334. The signal trace302 on the bottom surface 306 is referenced to power plane V_(CC) 334that is coupled to the GND plane 332 through decoupling capacitor 350.This coupling between the two planes will keep the high frequencyimpedance close to constant for the transition from one return plane toanother plane of a different DC voltage.

Internally mounting Z-directed components in a PCB greatly facilitatesthe PCB technique of using outer ground planes for EMI reduction. Withthis technique, signals are routed on the inner layers as much aspossible. FIG. 10 illustrates one embodiment of this technique. PCB 400is comprised of, from top to bottom, top ground layer 402, internalsignal layer 404, internal signal layer 406 and bottom ground layer 408.Ground layers 402 and 408 are on the top and bottom surfaces 400 t and400 b of PCB 400. A mounting hole 410, shown as a through-hole, extendsbetween the top and bottom surfaces 400 t and 400 b. Z-directedcomponent 420 is shown flush mounted in PCB 400. Z-directed component420 comprises body 422 having a center region 424 intermediate the top422 t and bottom 422 b of HI body 422 and two side channels 425 and 427on side surface 422 s.

Side channels 425 and 427 and wall 411 of hole 410 form plating wells413 and 415 respectively. Center region 424 is positioned within body422 and extends a distance approximately equal to the distanceseparating the two internal signal layers 404 and 406. Side channel 425extends from the bottom surface 422 b of body 422 to internal signallevel 406 while side channel 427 extends from top surface 422 t of body422 to internal signal level 404. Here, side channels 425 and 427 extendonly along a portion of side surface 422 s of body 422. Conductivechannel 426 extends through center region 424 but does not extend to thetop and bottom surfaces 422 t, 422 b of body 422. FIG. 5H illustrates apartial channel similar to side channel 427. Conductive channel 426 hasconductive traces 428 t and 428 b extending from the top 426 t andbottom 426 b of conductive channel 426 to side channels 427 and 425,respectively. While illustrated as separate elements, conductive channel426 and traces 428 t, 428 b may be one integrated conductor electricallyinterconnecting side channels 425, 427. As shown, conductive trace 428 bis connected to internal signal layer 406 via plated side channel 425and well 413 while trace 428 t connects to internal signal level 404 viaside channel 427 and well 415. Ground layers 402 and 408 are notconnected to Z-directed component 420 and are spaced away from mountinghole 410 as previously described for FIGS. 7 and 9. As shown by doubleheaded dashed arrow 430, a signal on signal layer 406 can be transmittedto signal layer 404 (or vice versa) via Z-directed component 420 througha path extending from well 413, side channel 425, trace 428 b,conductive channel 426, trace 428 t, side channel 427, and well 415 toallow the signal to remain on the inner layers of PCB 400 with groundlayers 402 and 408 providing shielding.

FIGS. 11 and 12 illustrate two additional example Z-directed componentsin the form of decoupling capacitors. In FIG. 11, a Z-directed capacitor500 is shown with a body 502 having a conductive channel 504 and twoside channels 506 and 508 extending along its length similar to thosepreviously described. Conductive channel 504 is shown connected to asignal 526. Vertically oriented interleaved partial cylindrical sheets510, 512 forming the plates of Z-directed capacitor 500 are connected toreference voltages such as supply voltage V_(CC) and ground (or anyother signals requiring capacitance) and are used with interveninglayers of dielectric material (not shown). Partial cylindrical sheet 510is connected to plated channel 506 which is connected to ground 520.Partial cylindrical sheet 512 is connected to plated channel 508 whichis connected to supply voltage V_(CC) 522. Sheets 510, 512 may be formedof copper, aluminum or other material with high conductivity. Thematerial between the partial cylindrical sheets is a material withdielectric properties. Only one partial cylindrical sheet is shownconnected to each of V_(CC) 522 and ground 520; however, additionalpartial cylindrical sheets may be provided to achieve the desiredcapacitance/voltage rating.

Another embodiment of a Z-directed capacitor is shown in FIG. 12 usingstacked layers connected to voltage V_(CC) or ground. Z-directedcapacitor 600 is comprised of center conductive channel 601 and a body605 comprised of a top member 605 t, a bottom member 605 b, and aplurality of layers or support members 610 (illustrated as disks)between the top and bottom members 605 t, 605 b.

Center conductive channel 601 extends through openings 615 in theassembled Z-directed capacitor 600 and openings 602 t and 602 b, all ofwhich are sized to closely receive the center conductor. Centerconductive channel 601 is electrically connectable to conductive traces603 t and 603 b on the top and bottom portions 605 t, 605 b forming asignal path for signal 626. This connection is made by plating orsoldering. Center conductive channel 601 is connected to signal 626 viaconductive trace 603 t. The bottom end of conductive channel 601 isconnected in a similar fashion to a signal trace (not shown) viaconductive trace 603 b.

Opposed openings 607 t and 608 t are provided at the edge of top portion605 t. Bottom portion 605 b is of similar construction as top portion605 t having opposed openings 607 b and 608 b provided at the edge.Between top and bottom portions 605 t, 605 b are a plurality of supportmembers 610, which provide the capacitive feature. Support members 610each have at least one opening 613 at their outer edge and an inner hole615 allowing for passage of conductive channel 601 therethrough. Asshown, two opposed openings 613 are provided in each support member 610.When assembled, the opposed openings 607 t, 607 b, 608 t, 608 b, and 613align to form opposed side channels 604 and 608 extending along the sidesurface of Z-directed capacitor 600. Side channel 604 is shown connectedto reference voltage such as ground 620 and side channel 606 to anotherreference voltage such as V_(CC) 622. Support members 610 may befabricated from a dielectric material and may be all of the same orvarying thickness allowing for choice in designing the desiredproperties for Z-directed capacitor 600.

Annular plating 617 is provided on one of top and bottom surfaces ofsupport member 610 or, if desired, on both surfaces. Annular plating isshown on the top surface of each support member but the location of theannular plating can vary from support member to support member. Annularplating 617 generally conforms to the shape of the support member andextends from one of the edge openings 613 toward the other if anadditional opening is provided. The annular plate 617 is of a diameteror dimension or overall size that is less than the diameter, dimensionor overall size of support member 610 on which it is affixed. While theplate 617 is described as annular, other shapes may also be usedprovided that the plating does not contact the center conductive channelor extend to the edge of the support member on which it is plated orotherwise affixed. The annular plate does contact one of the edgeopenings 613 but is spaced apart from the other openings if more thanone channel is present in the side surface of the body of Z-directedcapacitor 600. Also, there is an opening 619 in annular plate 617 havinga larger diameter than opening 615 in annular plate 617 through whichconductive channel 601 passes. Opening 619 has a larger diameter thanthat of conductive channel 601 leaving annular plate 617 spaced apartfrom conductive channel 601.

As illustrated, the support members 610 are substantially identicalexcept that when stacked, alternate members are rotated 180 degrees withrespect to the member above or below it. This may be referred to as a1-1 configuration. In this way, alternate members will be connected toone or the other of the two side channels. As shown in FIG. 12, theannular plating on the upper one of the two support members 610 isconnected to side channel 608 and voltage V_(CC) 622 while the annularplating on the lower one of the two support members 610 is connected toside channel 604 and ground 620. Other support member arrangements mayalso be used such as having two adjacent members connected to the samechannel with the next support member being connected to the oppositechannel which may be referred to as a 2-1 configuration. Otherconfigurations may include 2-2, 3-1 and are a matter of design choice.The desired capacitance or voltage rating determines the number ofsupport members that are inserted between top and bottom portions 605 t,605 b. Although not shown, additional dielectric members comprised ofdielectric material and similarly shaped to support members 610 may beinterleaved with support members 610. Based on design choice, only asingle channel may be used or more channels may be provided and/or theannular plating may be brought into contact with the center conductivechannel and not in contact with the side channels. Again, theembodiments for Z-directed capacitors are for purposes of illustrationand are not meant to be limiting.

With either design for a Z-directed capacitor, a second conductivechannel may be provided in parallel with the first conductive channelthat is disposed within the conductive plates to create a differentialdecoupling capacitor. Another embodiment of a Z-directed capacitor canbe constructed from FIG. 11 or FIG. 12 by connecting the centerconductive channel to one of the reference voltages at each supportmember that also has its annular plating connected to the same referencevoltage. This may be accomplished simply by connecting the conductivechannel to the annular plating as schematically illustrated by thejumper 621. In practice, the annular opening 619 in the annular plate617 would be sized so that the annular plate and conductive channel 601would be electrically connected. This component may be placed directlybelow a power pin or ball of an integrated circuit or other surfacemounted component for optimum decoupling placement.

Again, the Z-directed signal pass-through components illustrated inFIGS. 7-10 and the Z-directed decoupling capacitors illustrated in FIGS.11 and 12 provide merely a few example applications of a Z-directedcomponent. Those skilled in the art will appreciate that various othertypes of Z-directed components may be utilized including, but notlimited to, transmission lines, delay lines, T filters, decouplingcapacitors, inductors, common mode chokes, resistors, differential pairpass throughs, differential ferrite beads, diodes, or ESD protectiondevices (varistors).

The Z-directed components may be constructed on a commercial scaleaccording to various methods. For example, the following co-pendingUnited States patent applications, which are assigned to the assignee ofthe present application, describe various manufacturing processes forproducing Z-directed components: U.S. patent application Ser. No.13/222,748, filed Aug. 31, 2011, entitled “Die Press Process forManufacturing a Z-Directed Component for a Printed Circuit Board,” U.S.patent application Ser. No. 13/222,418, filed Aug. 31, 2011, entitled“Screening Process for Manufacturing a Z-Directed Component for aPrinted Circuit Board,” U.S. patent application Ser. No. 13/222,376,filed Aug. 31, 2011, entitled “Spin Coat Process for Manufacturing aZ-Directed Component for a Printed Circuit Board,” U.S. patentapplication Ser. No. 13/250,812, filed Sep. 30, 2011, entitled“Extrusion Process for Manufacturing a Z-Directed Component for aPrinted Circuit Board,” and U.S. patent application Ser. No. 13/284,084,filed Oct. 28, 2011, entitled “Continuous Extrusion Process forManufacturing a Z-Directed Component for a Printed Circuit Board.”

Transmission Line Impedance Control Through the Z-Directed Component

With reference to FIG. 13, a Z-directed capacitor 700 is shown accordingto one example embodiment. Z-directed capacitor 700 is substantially thesame as Z-directed capacitor 600 discussed above with respect to FIG. 12except that Z-directed capacitor 700 includes a pair of conductivechannels 730, 732 that extend through an interior portion of the body705 of the component along its length. Conductive channels 730, 732 arepositioned next to, and on opposite sides of, center conductive channel701. As discussed above, body 705 includes a top member 705 t, a bottommember 705 b, and a plurality of alternating support members 710, suchas disks, between the top and bottom members 705 t, 705 b. Centerconductive channel 701 forms a signal path for signal 726. Z-directedcapacitor 700 includes a pair of opposed side channels 740, 742 platedwith conductive material. In the example embodiment illustrated, sidechannel 740 is connected to a reference voltage such as ground (GND) 720and side channel 742 is connected to another voltage such as a supplyvoltage (V_(CC)) 722.

Conductive channels 730, 732 extend through corresponding openings inZ-directed capacitor 700 which are sized to closely receive therespective conductive channel 730, 732. FIGS. 14A and 14B show a firstsupport member 710 a and a second support member 710 b of Z-directedcapacitor 700, respectively, in closer detail. FIGS. 14A and 14B showside channels 740, 742 which are plated with conductive material. Asshown in FIG. 14A, in the example embodiment illustrated, conductivechannel 730 is connected to side channel 740 and GND 720 via annularplating 717 on the surface of first support member 710 a; however,annular plating 717 is spaced from and does not contact conductivechannel 732 or side channel 742. As shown in FIG. 14B, conductivechannel 732 is instead connected to side channel 742 and V_(CC) 722 viaannular plating 717 on the top surface of second support member 710 b.Conductive channel 730 and side channel 740 are spaced from and do notcontact annular plating 717 on second support member 710 b. Centerconductive channel 701 is spaced from and does not contact annularplating 717 on first support member 710 a or second support member 710b. Accordingly, in the example embodiment shown, conductive channels730, 732 and center conductive channel 701 may be referred to as forminga power-signal-ground (P-S-G) configuration as a result of theirphysical alignment. Alternatively, conductive channels 730, 732 andcenter conductive channel 701 may form a power-signal-power (P-S-P)configuration (by connecting both conductive channels 730, 732 to sidechannel 742 and V_(CC) 722) or a ground-signal-ground (G-S-G)configuration (by connecting both conductive channels 730, 732 to sidechannel 740 and GND 720). Further, as discussed above, support members710 a, 710 b may alternate to form any pattern desired, such as 1-1,2-1, 2-2, 3-1, etc.

As is known in the art, the transmission line impedance through signal726 depends in part on the distances between center conductive channel701 and side channels 740, 742 and the distances between centerconductive channel 701 and conductive channels 730, 732. The impedancealso depends on the capacitance between the alternating support members710. By positioning conductive channels 730, 732 next to centerconductive channel 701, the continuity of the transmission lineimpedance through signal 726 of Z-directed capacitor 700 is improved incomparison with Z-directed capacitor 600 shown in FIG. 12, which doesnot include the additional pair of interior conductive channels 730,732. Specifically, the placement of conductive channels 730, 732 closeto center conductive channel 701 minimizes the effects of side channels740, 742 and alternating support members 710 on the transmission lineimpedance through the component. Without conductive channels 730, 732,the alternating relationship of support members 610 of Z-directedcapacitor 600 alters the impedance of signal 626 as it moves through thecomponent. Conductive channels 730, 732 reduce this parasitic effect andpermit more constant impedance through the component as a result.

It will be appreciated that Z-directed capacitor 500 discussed abovewith respect to FIG. 11 may also be modified to include a pair ofconductive channels next to and on opposite sides of signal 526 in orderto reduce any discontinuities caused by conductive side channels 506,508 and sheets 510, 512. For example, FIG. 15 shows a Z-directedcapacitor 800 having a body 802. Z-directed capacitor 800 issubstantially the same as Z-directed capacitor 500 discussed above withrespect to FIG. 11 except that Z-directed capacitor 800 includes a pairof conductive channels 830, 832 that extend through an interior portionof the component along its length. A conductive channel 804 extendsthrough a center portion of body 802 along the length of body 802.Conductive channels 830, 832 are positioned next to, and on oppositesides of, center conductive channel 804. Body 802 also includes a pairof plated side channels 806, 808 that extend along its length asdiscussed above. In this example, conductive channel 804 is connected toa signal 826. Plated channel 806 is connected to ground 820 and platedchannel 808 is connected to supply voltage V_(CC) 822. Verticallyoriented interleaved partial cylindrical sheets 810, 812 forming theplates of Z-directed capacitor 800 are connected to side channels 806,808, respectively. A dielectric material is positioned between partialcylindrical sheets 810, 812. Depending on the configuration desired(i.e., P-S-G, P-S-P, or G-S-G), conductive channels 830, 832 may beconnected to plated channel 806 and ground (GND) 820 or plated channel808 and supply voltage (V_(CC)) 822. This connection may be establishedby connecting the conductive channel 830, 832 to one of itscorresponding cylindrical sheets 810, 812. Conductive channels 830, 832reduce the effects of side channels 806, 808 and sheets 810, 812 on thetransmission line impedance of signal 826 and thereby allow for moreconstant transmission line impedance through the component.

While the example embodiments illustrated in FIGS. 13-15 relate toZ-directed capacitors, any Z-directed component having a signal passingthrough an interior conductive channel may use a pair of adjacent,interior conductive channels to control the transmission line impedancethrough the signal. For example, FIG. 16 illustrates a Z-directed signalpass-through component 900 similar to component 200 discussed above withrespect to FIGS. 7 and 8. Component 900 includes a body 902 having a topsurface 902 t and a bottom surface 902 b. A conductive channel 904extends through a center portion of body 902 along its length.Conductive channel 904 is connected to a signal 920 by a trace 906 thatextends from conductive channel 904 across top surface 902 t to an edgeof component 900. Similarly, bottom surface 902 b of component 900includes a corresponding trace (not shown) that connects conductivechannel 904 to an edge of the component. Body 902 also includes a pairof conductive side channels 908, 910. A pair of conductive channels 912,914 extend through an interior portion of body 902 along its length nextto and on opposite sides of conductive channel 904. Each conductivechannel 912, 914 is connected to either side channel 908 or side channel910. This connection may be established by a trace on top surface 902 tor bottom surface 902 b or by connecting the conductive channel to itscorresponding side channel 912 or 914 on an internal portion of thecomponent between top surface 902 t and bottom surface 902 b. Where apower-signal-ground configuration is desired, conductive channel 912 maybe connected to side channel 908 which may in turn be connected to asupply voltage (V_(CC)) 922 and conductive channel 914 may be connectedto side channel 910 which may be in turn connected to a ground (GND)924. As discussed above, a ground-signal-ground or power-signal-powerconfiguration may also be used as desired.

FIG. 17 illustrates another example of a Z-directed signal pass-throughcomponent 1000. Component 1000 includes a body 1002 having a top surface1002 t and a bottom surface 1002 b. Unlike signal pass-through component900, body 1002 of component 1000 does not include side channels therein.A conductive channel 1004 extends through a center portion of body 1002along its length. Conductive channel 1004 is connected to a signal 1020by a trace 1006 that extends across top surface 1002 t and another trace(not shown) that extends across bottom surface 1002 b from conductivechannel 1004 to an edge of component 1000. A pair of conductive channels1008, 1010 extend through an interior portion of body 1002 along itslength next to and on opposite sides of conductive channel 1004. Eachconductive channel 1008, 1010 includes a respective trace 1012, 1014that extends from the conductive channel 1008, 1010 across top surface1002 t to the edge of component 1000. Again, bottom surface 1002 bincludes a corresponding pair of conductive traces that connectconductive channels 1008, 1010 to an edge of the component. Where apower-signal-ground configuration is desired, conductive channel 1008may be connected to a supply voltage V_(CC) 1022 by trace 1012 and thecorresponding trace on bottom surface 1002 b and conductive channel 1010may be connected to a ground GND 1024 by trace 1014 and thecorresponding trace on bottom surface 1002 b.

A pair of adjacent, interior conductive channels may also be used tocontrol the transmission line impedance through a component having adifferential signal including any number of signals passing through theinterior of the component. For example, FIG. 18 shows a Z-directedpass-through component 1100 having body 1102 that includes a pair ofconductive channels 1104, 1106 extending through a center portion ofbody 1102 along its length. Each conductive channel 1104, 1106 isconnected to a respective signal 1120, 1121 by a corresponding trace1108, 1110 on a top surface 1002 t and a bottom surface 1102 b of body1102. A pair of conductive channels 1112, 1114 extend through aninterior portion of body 1102 along its length next to and on oppositesides of conductive channels 1104, 1106 in order to provide moreconstant impedance through signals 1120, 1121. Each conductive channel1112, 1114 may be connected to a supply voltage (V_(CC)) or a groundvoltage by a respective trace across top surface 1102 t or bottomsurface 1002 b or via a connection to a respective plated side channel1116, 1118 as discussed above. Conductive channels 1112, 1114 may bothbe connected to the supply voltage V_(CC) or the ground or one ofconductive channels 1112, 1114 may be connected to supply voltage V_(CC)and the other to the ground. For a Z-directed component having multiplesignals, it will be appreciated that conductive channels 1112, 1114 willaid in controlling the common mode (or even mode) impedance but will notaffect the differential impedance between the signals.

In some embodiments of a Z-directed capacitor, it is preferred to have ahigh capacitance through the plates forming the capacitor whilemaintaining the transmission line impedance of the signal at a nominalvalue. FIG. 19 shows a Z-directed capacitor 1200. Z-directed capacitor1200 has a body 1202 that includes a stack of plated support members (orlayers) 1204, which may be arranged in a 1-1, 2-1, etc. configuration asdiscussed above with respect to FIGS. 12 and 13. A center conductivechannel 1206 extends through an interior portion of body 1202 along itslength forming a signal path. Body 1202 also includes a pair of platedside channels 1208, 1210 that may be connected to a supply voltage(V_(CC)) and a reference voltage (GND), respectively. A pair ofconductive channels 1212, 1214 extend through the interior of body 1202along its length next to and on opposite sides of center conductivechannel 1206 in order to reduce the impedance along the signal pathformed by center conductive channel 1206 as discussed above. Conductivechannels 1212, 1214 are connected to either side channel 1208 or sidechannel 1210 depending on the configuration desired (i.e., P-S-G, P-S-Por G-S-G).

Both a top portion 1202 t and a bottom portion 1202 b of body 1202include one or more support members 1216 having a relatively lowdielectric constant (∈_(r)), such as, for example between about 6 andabout 100 including all values and increments therebetween. One or moresupport members 1218 having a relatively high dielectric constant(∈_(r)) such as, for example between about 2,000 and about 25,000including all values and increments therebetween, are positioned betweentop portion 1202 t and bottom portion 1202 b. In the example embodimentillustrated, a first high dielectric support member 1218 a is positionedin the upper half of body 1202 and a second high dielectric supportmember 1218 b is positioned in the lower half of body 1202. However,high dielectric support members 1218 may be positioned and spaced asdesired. For example, multiple high dielectric support members 1218 maybe stacked one on top of the other in the center of body 1202 along itslength. High dielectric support members 1218 increase the capacitance ofZ-directed capacitor 1200.

As is known in the art, the transmission line impedance through thecomponent will increase with an increase in inductance and will decreasewith an increase in capacitance. Accordingly, depending on the magnitudeof the capacitance increase caused by the high dielectric layers 1218,the capacitance through conductive channel 1206 may be decreased in thehigh dielectric regions of body 1202 by making center conductive channel1206 narrower as it passes through the high dielectric regions of body1202. Making center conductive channel 1206 narrower in the highdielectric regions compensates for the increased capacitance that occursas a result of high dielectric support members 1216. In this manner, asubstantially constant impedance may be maintained through the signalpath formed by center conductive channel 1206. For example, in FIG. 19,center conductive channel 1206 is illustrated in dashed lines toindicate the signal path through the component. As shown, centerconductive channel 1206 narrows as it passes through first and secondhigh dielectric support layers 1218 a, 1218 b. Providing low dielectricregions at the top portion 1202 t and bottom portion 1202 b of body 1202prevents a disruptive impedance discontinuity as the signal travels froma trace on the PCB to a corresponding trace 1220 on body 1202 that isconnected to center conductive channel 1204. Accordingly, Z-directedcapacitor 1200 permits independent control of the capacitance and thetransmission line impedance. While only one signal path is illustratedthrough Z-directed capacitor 1200, varying low and high dielectriclayers 1216, 1218, respectively, may also be used with a differentialsignal component.

Depending on the magnitude of the capacitance increase caused by thehigh dielectric layers 1218, the inductance through center conductivechannel 1206 may also be adjusted by altering the positions ofconductive channels 1212, 1214 relative to center conductive channel1206 in order to further maintain the constant transmission lineimpedance through the signal path. For example, in the high dielectricregions of body 1202, conductive channels 1212, 1214 may be moved awayfrom center conductive channel 1206 in order to compensate for theincreased capacitance that results from the high dielectric regions byincreasing the inductance.

With reference to FIG. 20, a Z-directed capacitor 1300 is shownaccording to another example embodiment. Like Z-directed capacitor 800shown in FIG. 15, Z-directed capacitor 1300 has a body 1302 thatincludes vertically oriented interleaved partial cylindrical sheets1304, 1306, which may be arranged in a 1-1, 2-1, etc. configuration asdesired. A center conductive channel 1308 extends through an interiorportion of body 1302 along its length forming a signal path. Body 1302also includes a pair of plated side channels 1310, 1312 that may beconnected to a supply voltage (V_(CC)) and a reference voltage (GND),respectively. Cylindrical sheets 1304, 1306 are connected to sidechannels 1310, 1312, respectively. A dielectric material is positionedbetween partial cylindrical sheets 1304, 1306. A pair of conductivechannels 1314, 1316 extend through the interior of body 1302 along itslength next to and on opposite sides of center conductive channel 1308in order to reduce the impedance along the signal path formed by centerconductive channel 1308 as discussed above. Conductive channels 1314,1316 may be connected to either side channel 1310 via sheet 1304 or sidechannel 1312 via sheet 1306 depending on the configuration desired(i.e., P-S-G, P-S-P or G-S-G).

An outer portion of body 1302 has a relatively high dielectric constant(∈_(r)), such as, for example between about 6 and about 100 includingall values and increments therebetween, forming a high dielectric outerregion 1318. An inner portion of body 1302 spaced inward from the sidesurface of body 1302 has a relatively low dielectric constant (∈_(r))such as, for example between about 2,000 and about 25,000 including allvalues and increments therebetween, forming a low dielectric innerregion 1320. Sheets 1304, 1306 of Z-directed capacitor 1300 run throughhigh dielectric outer region 1318 along the length of body 1302 therebyincreasing the capacitance of sheets 1304, 1306. Center conductivechannel 1308 is connected to an edge of the component by a trace 1322across a top surface 1302 t of the component. A bottom surface 1302 bincludes a corresponding trace (not shown). Center conductive channel1308 runs through low dielectric inner region 1320 in body 1302 alongits length in order to maintain a substantially constant transmissionline impedance. As a result, by providing Z-directed capacitor 1300 witha high dielectric outer region 1318 for the plates of the capacitor andlow dielectric inner region 1320 for the signal path, a high capacitanceand a substantially constant transmission line impedance may beachieved.

Further, the top and bottom of body 1302 where trace 1322 and thecorresponding bottom trace for the signal path pass may be formed of thelow dielectric constant material in order to prevent an impedancediscontinuity as the signal travels from a trace on the PCB to trace1322 or the corresponding bottom trace. Alternatively, depending on themagnitude of the capacitance increase caused by the high dielectricouter region 1318, the portions of the respective traces traveling overhigh dielectric outer region 1318 may be narrowed in order to decreasethe capacitance therethrough. For example, as shown in FIG. 20, trace1322 includes a wider portion 1322 a that travels across lowerdielectric inner region 1320 and a narrower portion 1322 b that travelsacross higher dielectric outer region 1318. The varied width of trace1322 compensates for the increased capacitance that results from highdielectric outer region 1318 to help maintain a substantially constantimpedance therethrough. Further, the width of center conductive channel1308 is substantially the same as wider portion 1322 a of trace 1322 inorder to maintain a constant impedance through the component. Again,while only one signal path is illustrated through Z-directed capacitor1300, a differential signal component may also be formed having a lowdielectric inner region 1320 and a high dielectric outer region 1318.

While Z-directed capacitors are illustrated in FIGS. 19 and 20, otherZ-directed components may benefit from having varying dielectricregions. For example, FIG. 21 shows a Z-directed delay line component1400 having a body 1402 that includes a conductive delay line 1404therein forming a signal path. Body 1402 includes a trace 1406 that runsacross its top surface 1402 t and connects delay line 1404 to an edge ofthe component. Bottom surface 1402 b of body 1402 includes a similartrace (not shown) that connects the other end of delay line 1404 to theedge of the component. Body 1402 also includes a relatively lowdielectric region 1408 and a relatively high dielectric region 1410. Inthe example embodiment illustrated, high dielectric region 1410 ispositioned in a center portion of body 1402 along its length while lowdielectric region 1408 is split into two halves 1408 a, 1408 bpositioned at the top and bottom portion, respectively, of body 1402along its length. However, the size and placement of each dielectricregion may be optimized to achieve the desired delay. Further, thenumber of different dielectric regions as well as their respectivedielectric properties may also be optimized to achieve the desireddelay. As a signal travels through component 1400 on delay line 1404, itwill be slowed as it passes through the high dielectric region 1410. Thesignal may be further delayed by altering its path through thecomponent, such as by providing a zigzag or spiral pattern. While theexample embodiment illustrated shows the signal entering the componentfrom one end and leaving from the other, it will be appreciated that thesignal may enter and leave at the same end or it may enter and/or leavealong a side surface of the component, for example by providing a platedside channel as discussed above.

Reduction of the Net Loop Area of the Z-Directed Component

FIG. 22 shows a Z-directed capacitor 1500 having a body 1502 thatincludes four plated side channels 1504, 1506, 1508, 1510. Side channels1504, 1506, 1508, 1510 are spaced substantially equally (about 90degrees) from each other around the edge of the component. Body 1502 iscomprised of stacked layers or support members 1512. Each support member1512 is composed of dielectric material and is plated with conductivematerial to form the plates of the capacitor as discussed above. In oneembodiment, side channels 1504 and 1508 are connected to a referencevoltage (GND) 1514 and side channels 1506, 1510 are connected to avoltage supply (V_(CC) 1516.)

As illustrated in FIG. 23, one application of Z-directed capacitor 1500is as a zero lead-length decoupling capacitor under an integratedcircuit (IC) 1550 utilizing a ball grid array (BGA) (or a micro-BGA)1552 having conductive balls 1554. For clarity, only one ball 1554 isshown in FIG. 23. In this embodiment, a conductive (e.g., copper) ballpad 1584 is electrically connected to each plated side channel 1504,1506, 1508, 1510. In one embodiment, each ball pad 1584 is positioned ontop of and connected to a conductive channel 1590 through an interiorportion of the component. Conductive channels 1590 are connected to arespective side channel 1504, 1506, 1508, 1510 on an internal layer ofZ-directed capacitor 1500. Alternatively, ball pads 1584 may beconnected to side channels 1504, 1506, 1508, 1510 by a trace 1592 acrossthe top surface 1502 t of Z-directed capacitor 1500. Further, ball pads1584 may be positioned directly on top of and connected to plated sidechannels 1504, 1506, 1508, 1510; however, in this configuration, thereis a risk that the conductive material of balls 1554 will be pulled intoside channels 1504, 1506, 1508, 1510 potentially disrupting theelectrical connection between the ball 1554 and IC 1550. The conductiveballs 1554 of the BGA 1552 are placed on top of ball pads 1584 when theintegrated circuit 1550 is installed on PCB 1580. As discussed ingreater detail below, wire to bonds connect the balls 1554 to thesubstrate of IC 1550. This geometry creates a loop that follows the pathbetween side channels 1506, 1510 connected to V_(CC) 1516 and sidechannels 1504, 1508 connected to GND 1514 through Z-directed capacitor1500, balls 1554 and IC 1550.

FIG. 24 illustrates a schematic depiction of the various currents(labeled “I”) and magnetic fluxes (labeled “B”) of the loop. Thecurrents (I) having direction vectors moving from V_(CC) 1516 to GND1514 create respective magnetic fluxes (B). As shown in FIG. 24, byproviding four equally spaced conductive side channels 1504, 1506, 1508,1510 with GND 1514 passing through opposite channels 1504, 1508 andV_(CC) 1516 passing through the other opposite channels 1506, 1510, thedirection of the magnetic flux vector (B) of each loop is opposite thatof the magnetic flux vector (B) on the opposite side. For example,magnetic flux vector B1 and magnetic flux vector B3, positioned onopposite sides of Z-directed capacitor 1500, have opposite directions.Similarly, the directions of magnetic flux vector B2 and magnetic fluxvector B4 are also opposite one another. As a result, the net magneticflux (and net loop area) of Z-directed capacitor 1500 is significantlyreduced thereby also reducing the inductance of the component. This aidsin preventing unwanted voltage drops and reduces the radiatedelectromagnetic emissions from the component. Although Z-directedcapacitor 1500 is illustrated as having four equally spaced sidechannels 1504, 1506, 1508, 1510, it will be appreciated that netmagnetic flux cancellation may also be achieved using four equallyspaced conductive channels through an interior portion of the component,such as by providing four conductive channels that are positioned nearthe edge of the component and spaced apart by 90 degrees.

FIGS. 25A and 25B show a first support member 1512 a and a secondsupport member 1512 b of Z-directed capacitor 1500, respectively, incloser detail. FIGS. 25A and 25B show side channels 1504, 1506, 1508,1510 plated with conductive material. As shown in FIG. 25A, sidechannels 1504 and 1508 connected to GND 1514 are connected to each otheracross the top surface of first support member 1512 a via annularplating 1518. In contrast, side channels 1506 and 1510 connected toV_(CC) 1516 are each spaced from annular plating 1518 on first supportmember 1512 a. As shown in FIG. 25B, side channels 1506 and 1510connected to V_(CC) 1516 are connected to each other across the topsurface of second support member 1512 b via annular plating 1518. Sidechannels 1504 and 1508 connected to GND 1514 are each spaced fromannular plating 1518 on second support member 1512 b. As discussedabove, support members 1512 a and 1512 b may alternate to form anypattern desired, such as 1-1, 2-1, 2-2, 3-1, etc.

FIGS. 25C and 25D show alternative support members 1512 c and 1512 d foruse where it is desired to decouple more than two voltages in Z-directedcapacitor 1500. As shown in FIG. 25C, side channel 1504 is connected toa first voltage V1 and side channel 1508 is connected to a secondvoltage V2 on support member 1512 c. Annular plating 1518 extends fromeach of side channels 1504 and 1508 and covers a majority of the topsurface of support member 1512 c. However, the plating 1518 connected toside channel 1504 does not contact the plating 1518 connected to sidechannel 1508. Further, plating 1518 on support member 1512 c is spacedfrom side channels 1506 and 1510. As shown in FIG. 25D, side channel1506 is connected to a third voltage V3 and side channel 1510 isconnected to a fourth voltage V4 on support member 1512 d. Annularplating 1518 extends from each of side channels 1506 and 1510 and coversa majority of the top surface of support member 1512 d. Again, theplating 1518 connected to side channel 1506 does not contact the plating1518 connected to side channel 1510. Further, plating 1518 on supportmember 1512 d is spaced from side channels 1504 and 1508. By alternatingsupport members 1512 c and 1512 d, a Z-directed capacitor may be formedthat can couple four different voltages together. Voltages V1, V2, V3and V4 may be any voltage desired; for example, one may be a referencevoltage and the others supply voltages referenced thereto.

Combinations of these support members 1512 a, 1512 b, 1512 c, 1512 d mayalso be used as desired. For example, where one pair of voltages isshorted together but the other is not, such as for a system with acommon ground and two power supplies (e.g., a positive voltage supplyand a negative voltage supply with respect to ground), Z-directedcapacitor 1500 may be formed by alternating support member 1512 a withsupport member 1512 d or by alternating support member 1512 b withsupport member 1512 c.

It will be appreciated that support members 1512 c and 1512 d provideless field cancellation than support members 1512 a and 1512 b; however,support members 1512 c and 1512 d may reduce the number of componentsneeded to form the desired circuit by providing the ability to decouplemore voltages using a single Z-directed capacitor. For example, where IC1550 requires 2 voltages to be decoupled, such as a core voltage and aninput/output (I/O) voltage, Z-directed capacitor 1500 formed byalternating support members 1512 a and 1512 d or support members 1512 band 1512 c may be placed on PCB 1580 and connected to the core voltageand the I/O voltage as well as their respective reference voltages. Thisgreatly reduces the loop area in comparison with conventional decouplingmethods, which typically use a pair of surface mounted capacitors, onefor each of the core voltage and the I/O voltage, connected to the IC bytraces across the surface of the PCB.

For example, FIGS. 26A and 26B show a top schematic view and a schematicdiagram, respectively, of a portion of a prior art IC 2500 having a BGA2502 made up of conductive balls 2504 mounted on correspondingconductive ball pads (not shown beneath balls 2504) of a PCB 2520. IC2500 includes a core region 2510 and an I/O region 2512 which eachcontain many logic gates as is known in the art. A pair of conventionalsurface mounted capacitors 2530, 2540 are mounted on PCB 2520 andconnected to I/O region 2512 and core region 2510, respectively.Specifically, capacitor 2530 is connected to the supply voltage V_(I) ofI/O region 2512 by a trace 2532 across the surface of PCB 2520 to ball2504 a and to ground voltage GND by a trace 2534 to ball 2504 b.Capacitor 2540 is connected to a supply voltage V_(C) of core region2510 by a trace 2542 to ball 2504 c and to ground GND by a trace 2544 toball 2504 d. The current loop (I₁) formed between capacitors 2530, 2540,core region 2510 and I/O region 2512 is shown in dashed lines in FIGS.26A and 26B.

FIGS. 27A and 27B show a top schematic view and a schematic diagram,respectively, of a portion of IC 2600 having a BGA 2602 of conductiveballs 2604 mounted on corresponding conductive ball pads (not shownbeneath balls 2604) of a PCB 2620. Like prior art IC 2500, IC 2600includes a core region 2610 and an I/O region 2612 which each containlogic gates. In the example embodiment shown in FIGS. 27A and 27B,surface mounted capacitors 2530, 2540 have been replaced with a singleZ-directed capacitor, such as Z-directed capacitor 1500, mounted in amounting hole in PCB 2620 and connected to both core region 2610 and I/Oregion 2612. Specifically, side channel 1504 of Z-directed capacitor1500 is connected to the supply voltage V_(I) of I/O region 2612 by ball2604 a, side channel 1508 is connected to a supply voltage V_(C) of coreregion 2610 by ball 2604 c and side channels 1506, 1510 are connected toground voltage GND by ball 2604 b, 2604 d. The current loop (I₂) formedbetween Z-directed capacitor 1500, core region 2610 and I/O region 2612is shown in dashed lines in FIGS. 27A and 27B. As shown, the loop areaof current path I₂ utilizing Z-directed capacitor 1500 is significantlyreduced in comparison with the loop area of current path I₁ utilizingconventional surface mount capacitors 2530, 2540. Further, Z-directedcapacitor 1500 positioned directly beneath IC 2600 occupiessignificantly less space on PCB 2620 than surface mount capacitors 2530,2540 which are spaced from IC 2500 and connected to IC 2500 via traceson PCB 2520.

FIG. 28 shows a Z-directed capacitor 1600 having a body 1602 that, likeZ-directed capacitor 1500, includes four plated side channels 1604,1606, 1608, 1610. Side channels 1604, 1606, 1608, 1610 are spacedsubstantially equally (about 90 degrees) from each other around the edgeof the component. Z-directed capacitor also includes a center conductivechannel 1612 for passing a signal 1614 through the component. Body 1602is comprised of stacked layers or support members 1616. Each supportmember 1616 is composed of dielectric material and is plated withconductive material to form the plates of the capacitor as discussedabove. In one embodiment, side channels 1604 and 1608 are connected to areference voltage (GND) 1618 and side channels 1606, 1610 are connectedto a voltage supply (V_(CC)) 1620. As discussed above, spacing platedside channels 1604, 1606, 1608, 1610 equally around the edge of thecomponent reduces the net magnetic flux of Z-directed capacitor 1600.

FIGS. 29A and 29B show a first support member 1616 a and a secondsupport member 1616 b of Z-directed capacitor 1600, respectively, incloser detail. FIGS. 29A and 29B show side channels 1604, 1606, 1608,1610 and center channel 1612 plated with conductive material. As shownin FIG. 29A, side channels 1604 and 1608 connected to GND 1618 areconnected to each other across the top surface of first support member1616 a via annular plating 1622. In contrast, side channels 1606 and1610 connected to V_(CC) 1620 are each spaced from annular plating 1622on first support member 1616 a. As shown in FIG. 29B, side channels 1606and 1610 connected to V_(CC) 1620 are connected to each other across thetop surface of second support member 1616 b via annular plating 1622.Side channels 1604 and 1608 connected to GND 1618 are each spaced fromannular plating 1622 on second support member 1616 b. As shown in FIG.29A and FIG. 29B, center conductive channel 1612 is spaced from annularplating 1622 on support member 1616 a and support member 1616 b. Asdiscussed above, support members 1616 a and 1616 b may alternate to formany pattern desired, such as 1-1, 2-1, 2-2, 3-1, etc.

FIGS. 29C and 29D show alternative support members 1616 c and 1616 d foruse where it is desired to decouple more than two voltages in Z-directedcapacitor 1600 as discussed above. As shown in FIG. 29C, side channel1604 is connected to a first voltage V1 and side channel 1608 isconnected to a second voltage V2 on support member 1616 c. Annularplating 1622 extends from each of side channels 1604 and 1608 and coversa majority of the top surface of support member 1616 c. However, theplating 1622 connected to side channel 1604 does not contact the plating1622 connected to side channel 1608. Further, plating 1622 on supportmember 1616 c is spaced from side channels 1606 and 1610. As shown inFIG. 29D, side channel 1606 is connected to a third voltage V3 and sidechannel 1610 is connected to a fourth voltage V4 on support member 1616d. Annular plating 1622 extends from each of side channels 1606 and 1610and covers a majority of the top surface of support member 1616 d.Again, the plating 1622 connected to side channel 1606 does not contactthe plating 1622 connected to side channel 1610. Further, plating 1622on support member 1616 d is spaced from side channels 1604 and 1608. Asshown in FIG. 29C and FIG. 29D, center conductive channel 1612 is spacedfrom annular plating 1622 on support member 1616 c and support member1616 d.

As discussed above, various combinations of these support members 1616a, 1616 b, 1616 c, 1616 d may be used as desired, such as to decouple acore voltage and an input/output (I/O) voltage of an integrated circuit.Although Z-directed capacitor 1600 is depicted as having only one signalpath 1614, additional conductive channels may be provided to accommodatea differential signal. Further, a pair of additional conductive channelsmay be positioned next to and on opposite sides of center conductivechannel 1612 in order to reduce the transmission line impedance throughthe component as discussed above with respect to FIGS. 13-18.

Ball Grid Array Placement with PCBs Using a Z-Directed Component

In conventional BGA (and micro-BGA) configurations, there is typicallyonly room for one PCB via in the middle of a group of four ball pads. Aball pad may be placed on a PCB via; however, in some instances, theboard via may pull the conductive material of the ball into the viareducing the ball size and creating yield issues. It is possible to fillthe via in advance in order to avoid this issue but additionalprocessing steps are required. In contrast, the Z-directed componentsdescribed herein do not possess holes that would pull the conductivematerial of the ball. Rather, the Z-directed components are mounted in ahole in the PCB and may include interior conductive channels and/orconductive side channels that are exposed on a top surface of thecomponent. A conductive ball pad may be connected to the exposedconductive channels making the Z-directed components compatible with aBGA process.

The Z-directed components can accommodate a variety of configurations toimprove the decoupling of a BGA integrated circuit. For example, FIG. 30shows a top surface 1702 of a Z-directed component 1700 mounted in a PCB1790 that includes a pair of conductive side channels 1704, 1706 onopposite sides of the component and four equally spaced conductivechannels 1708, 1710, 1712, 1714 through an interior portion of thecomponent. In the example embodiment illustrated, side channel 1704 isconnected to a reference voltage (GND) 1716 and side channel 1706 isconnected to a voltage supply (V_(CC)) 1718. This connection may beestablished on an interior layer of PCB 1790. In the example embodimentshown, side channels 1704, 1706 are positioned to effectively form boardvias that provide the connections to GND 1716 and V_(CC) 1718.Conductive channels 1708 and 1712 are connected to GND 1716 such as byconnecting side channel 1704 to conductive channels 1708, 1712 on aninternal layer of the component as discussed above. Conductive channels1710 and 1714 are connected to V_(CC) 1718 by similar means. Conductiveball pads 1720, 1722, 1724, 1726 are connected to conductive channels1708, 1710, 1712, 1714, respectively, to receive corresponding balls(not shown) of the BGA. In this embodiment, each ball pad 1720, 1722,1724, 1726 is positioned on the surface of Z-directed component 1700,which is inserted into a mounting hole in PCB 1790 so that ball pads1720, 1722, 1724, 1726 are flush with the other ball pads of PCB 1790.Further, as discussed above with respect to FIG. 24, the relativepositioning of conductive channels 1708, 1712 connected to GND 1716 andconductive channels 1710, 1714 connected to V_(CC) 1718 providesmagnetic flux cancellation to reduce the electromagnetic emissions ofZ-directed component 1700.

FIG. 31 shows Z-directed component 1700 mounted in a mounting hole 1792of a PCB 1790. An integrated circuit 1750 is mounted on PCB 1790 using aball grid array 1760. As is known in the art, IC 1750 may be operativelyconnected to BGA 1760 within a common package 1752 (schematically shownin dashed lines). Conductive channels 1708, 1710, 1712, 1714 areconnected to corresponding balls 1762, 1764, 1766, 1768, respectively,of BGA 1760. The locations of balls 1762, 1764, 1766, 1768 are shown ascircles on a top side of BGA 1760. Balls 1762, 1764, 1766, 1768 areconnected to a substrate 1754 of IC 1750 by wire bonds 1772, 1774, 1776,1778, respectively, within package 1752. Specifically, wire bonds 1772,1774, 1776, 1778 connect balls 1762, 1764, 1766, 1768 to correspondingcontacts 1782, 1784, 1786, 1788, respectively, on substrate 1754.Accordingly, contacts 1782 and 1786 are connected to GND 1716 whilecontacts 1784 and 1788 are connected to V_(CC) 1718. Contact 1782connected to GND 1716 is positioned next to contact 1788 connected toV_(CC) 1718. Similarly, contact 1784 connected to V_(CC) 1718 ispositioned next to contact 1786 connected to GND 1716. This permits themagnetic flux reduction achieved by Z-directed component 1700 to extendfrom the component through wire bonds 1772, 1774, 1776, 1778 into IC1750. In the example embodiment illustrated, contacts 1782, 1784, 1786,1788 form a power-ground-ground-power configuration. Alternatively, aground-power-power-ground configuration may also be used as desired. Inthis manner, the magnetic flux of one power-ground pair will tend tocancel with the other pair thereby reducing the inductance andelectromagnetic emissions from Z-directed component 1700 through ballpads 1720, 1722, 1724, 1726, balls 1762, 1764, 1766, 1768, and wirebonds 1772, 1774, 1776, 1778.

FIG. 32A shows a Z-directed component 1800 similar to Z-directedcomponent 1700 except that Z-directed component 1800 is not large enoughfor the ball pads to be completely positioned on the component.Z-directed component 1800 includes four equally spaced conductivechannels 1808, 1810, 1812, 1814 through an interior portion of thecomponent. Z-directed component 1800 does not require side channels butmay instead connect to PCB vias 1804, 1806 by respective board traces1805, 1807 to establish connections with GND 1816 and V_(CC) 1818. GND1816 and V_(CC) 1818 may then be connected to conductive channels 1808,1812 and conductive channels 1810, 1814, respectively, via correspondingtraces (not shown) on the top surface, bottom surface or an internallayer of Z-directed component 1800 depending on whether board traces1805, 1807 are positioned on the top or bottom surface of the PCB or aninternal layer. Conductive ball pads 1820, 1822, 1824, 1826 areconnected to conductive channels 1808, 1810, 1812, 1814, respectively.In this embodiment, each ball pad 1820, 1822, 1824, 1826 is sharedbetween a top surface 1802 of the Z-directed component 1800 and the topsurface of the PCB. Although Z-directed component is illustrated ashaving four equally spaced interior conductive channels 1808, 1810,1812, 1814, it will be appreciated that conductive side channels may beused as well. In this alternative, each ball pads 1820, 1822, 1824, 1826is positioned on a respective side channel.

FIG. 32B illustrates an additional example Z-directed component 1900similar to Z-directed component 1700 except that Z-directed component1900 may accommodate four distinct voltages with four ball pads.Z-directed component 1900 includes four conductive side channels 1904,1905, 1906, 1907 spaced equally around the edge of the component.Z-directed component 1900 further includes four equally spacedconductive channels 1908, 1910, 1912, 1914 through an interior portionof the component. In the example embodiment illustrated, side channels1904, 1905, 1906, 1907 are connected to a first voltage (V1), a secondvoltage (V2), a third voltage (V3) and a fourth voltage (V4),respectively. Each of side channels 1904, 1905, 1906, 1907 are alsoconnected to a respective conductive channel 1908, 1910, 1912, 1914.Conductive ball pads 1920, 1922, 1924, 1926 are positioned on a topsurface 1902 of component 1900 on conductive channels 1908, 1910, 1912,1914, respectively. In this embodiment, Z-directed component 1900 may beconnected to up to four distinct voltages. Alternatively, one or more ofvoltages V1 through V4 may be the same. For example, V1 may be the sameas V3 and/or V2 may be the same as V4. In one embodiment, V1 and V3 area common reference voltage and V2 and V4 are a common voltage supply. Inanother embodiment, V1 and V3 are a common reference voltage, V2 is apositive voltage supply and V4 is a negative voltage supply relative tothe reference voltage.

FIG. 32C shows a Z-directed component 2000 similar to Z-directedcomponent 1900 except that Z-directed component 2000 is not large enoughfor the ball pads to be completely positioned on the component.Z-directed component 2000 includes four equally spaced conductivechannels 2008, 2010, 2012, 2014 through an interior portion of thecomponent; however, conductive side channels may be used instead.Z-directed component 2000 does not include side channels but insteadconnects to PCB vias 2004, 2005, 2006, 2007 via respective board traces2030, 2032, 2034, 2036 to establish the connections with voltages V1through V4 as discussed above. Conductive ball pads 2020, 2022, 2024,2026 are connected to conductive channels 2008, 2010, 2012, 2014,respectively, such that each ball pad 2020, 2022, 2024, 2026 overlapsbetween Z-directed component 2000 and the PCB.

FIG. 32D illustrates another example Z-directed component 2100 thatincludes connections to six ball pads. Z-directed component 2100includes a pair of conductive side channels 2104, 2106 on opposite sidesof the component. Z-directed component 2100 further includes six equallyspaced conductive channels 2108, 2110, 2112, 2114, 2116, 2118 through aninterior portion of the component; however, side channels may also beused. In the example embodiment illustrated, side channels 2104, 2106are connected to GND 2120 and V_(CC) 2122, respectively. In thisembodiment, side channels 2104, 2106 are positioned to effectively formboard vias that form the connections to GND 2120 and V_(CC) 2122.Conductive channels 2108, 2112, 2116 are connected to GND 2120 andconductive channels 2110, 2114, 2118 are connected to V_(CC) 2122. Sixconductive ball pads 2130, 2132, 2134, 2136, 2138, 2140 are connected toZ-directed component 2100 to receive corresponding balls (not shown) ofthe BGA. Specifically, ball pads 2130, 2132, 2136, 2138 are positionedon the PCB and are spaced from Z-directed component 2100. Ball pads2130, 2132, 2136, 2138 are connected to conductive channels 2108, 2110,2114, 2116, respectively, by corresponding traces 2140, 2142, 2144, 2146across the PCB and Z-directed component 2100. Ball pads 2134, 2140 areshared by the PCB and Z-directed component 2100 and are connecteddirectly to conductive channels 2112, 2118, respectively.

FIG. 32E illustrates yet another example embodiment of a Z-directedcomponent 2200 that includes connections to eight ball pads. Z-directedcomponent 2200 includes four conductive side channels 2204, 2205, 2206,2207 equally spaced around the edge of the component. Z-directedcomponent 2200 further includes a total of eight spaced conductivechannels 2208, 2210, 2212, 2214, 2216, 2218, 2220, 2222 through aninterior portion of the component; however, side channels may also beused in place of the interior channels located near the edge of thecomponent. In the example embodiment illustrated, side channels 2204,2206 are connected to GND 2230 and side channels 2205, 2207 areconnected to V_(CC) 2232. Conductive channels 2208, 2216, 2218, 2222 areconnected to GND 2230 and conductive channels 2210, 2212, 2214, 2220 areconnected to V_(CC) 2232. Eight conductive ball pads 2240, 2242, 2244,2246, 2248, 2250, 2252, 2254 are connected to Z-directed component 2200to receive corresponding balls (not shown) of the BGA. Specifically,ball pads 2240, 2242, 2244, 2246, 2248, 2250, 2252, 2254 are positionedon and connected to conductive channels 2208, 2210, 2212, 2214, 2216,2218, 2220, 2222, respectively.

FIGS. 30 and 32A through 32E are not intended to be limiting and areinstead intended to illustrate the flexibility available in utilizing aZ-directed component with a BGA. As discussed above, any number ofconnections may be made between a Z-directed component and a BGAdepending on the sizes of the Z-directed component and the BGA. Further,connections between a Z-directed component and a BGA ball may be madeusing a ball pad positioned on the Z-directed component, a ball padshared by the Z-directed component and the board, or by connecting aball pad on the board to the Z-directed component using a surface traceor internal connection. The Z-directed component may be connected to thedesired voltages by any suitable connection, such as by using a trace ona top, bottom or intermediate layer of the board or by providing aconnection to a conductive side channel of the Z-directed component.

It will be appreciated that the Z-directed components may also beconnected to an integrated circuit using a flip chip bonding method. Inthis method, conductive pads are positioned on the surface of theintegrated circuit substrate. Solder dots are then deposited on each ofthe pads. The integrated circuit substrate is then flipped andpositioned to face and mate with corresponding contacts on the surfaceof the PCB. The conductive channels (either side or interior) exposed onthe top or bottom surface of a Z-directed component may comprise aportion of these contacts on the PCB. After the solder dots are matedwith the PCB and/or the Z-directed component(s), the solder is melted,such as by applying a hot air reflow. The mounted chip is thenunderfilled typically using an electrically insulating adhesive tocomplete the bond. Further, the Z-directed components may also bedirectly or indirectly connected to one or more power pins of anintegrated circuit.

In some embodiments, a chamfer, dome or other form of taper or lead-inof at least one of the top and bottom surface of the Z-directedcomponent is desired in order to ease insertion of the Z-directedcomponent into the mounting hole in the PCB. For example, FIG. 33A showsa Z-directed component 2300 having a dome 2302 formed on an end thereofFIG. 33B shows a Z-directed component 2304 having a chamfered end 2306.The dome 2302 or chamfer 2306 may be part of the component or attachedthereto. In one embodiment, the dome 2302 or chamfer 2306 is a separatepart that is partially inserted into the mounting hole in the PCB. Inthis embodiment, the Z-directed component is then inserted behind thedome 2302 or chamfer 2306 to push it through the mounting hole causingthe dome 2302 or chamfer 2306 to expand the mounting hole and preventthe component from cutting or tearing the PCB. Where the dome 2302 orchamfer 2306 is attached to the Z-directed component, it may beconfigured to remain attached to the Z-directed component followinginsertion into the mounting hole in the PCB or it may be used tofacilitate insertion and then removed.

With reference to FIGS. 34A and 34B, manufacturing variations in thethickness of the PCB and the length of the Z-directed component mayprevent the Z-directed component from being perfectly flush with boththe top and bottom surfaces of the PCB. As a result, in one embodiment,a conductive strip 2412 is formed along a side surface 2410 s of aZ-directed component 2410. Conductive strip 2412 runs along side surface2410 s to either the top or bottom surface of Z-directed component 2410.Conductive strip 2412 may be applied after the Z-directed component 2410is formed. In the example embodiment illustrated, conductive strip 2412runs along side surface 2410 s to a top surface 2410 t of Z-directedcomponent 2410. In this manner, conductive strip 2412 forms a bridgebetween a trace 2414 on the respective top or bottom surface ofZ-directed component 2410 and a trace 2416 on a PCB 2418 when the top orbottom surface of the Z-directed component extends past thecorresponding top or bottom surface of the PCB. As a result, trace 2414on Z-directed component 2410 is able to connect to trace 2416 on PCB2418 even if the top or bottom surface of Z-directed component 2410 isnot flush with the corresponding top or bottom surface of PCB 2418. Inthe example configuration illustrated in FIG. 34B, conductive strip 2412runs from top surface 2410 t of Z-directed component 2410 to a pointalong side surface 2410 s that is below the top surface of the PCB 2418.In one embodiment, conductive strip 2412 extends into the side ofZ-directed component 2410 both to decrease its resistance and to ensurethat it is not removed if another feature such as a taper is laterapplied to Z-directed component 2410.

The foregoing description of several embodiments has been presented forpurposes of illustration. It is not intended to be exhaustive or tolimit the application to the precise forms disclosed, and obviously manymodifications and variations are possible in light of the aboveteaching. It is understood that the invention may be practiced in waysother than as specifically set forth herein without departing from thescope of the invention. It is intended that the scope of the applicationbe defined by the claims appended hereto.

What is claimed is:
 1. A printed circuit board, comprising: a Z-directedcomponent mounted in a mounting hole in the printed circuit board, theZ-directed component including: a body having a top surface, a bottomsurface and a side surface, a portion of the body being composed of aninsulator; and four conductive channels extending through a portion ofthe body along the length of the body, the four conductive channelsbeing spaced substantially equally around a perimeter of the body, afirst and a second of the four conductive channels being positionedopposite each other and a third and a fourth of the four conductivechannels being positioned opposite each other; an integrated circuitmounted on a surface of the printed circuit board, the integratedcircuit having a ball grid array that includes four conductive ballselectrically connected to a corresponding one of the four conductivechannels of the Z-directed component; and four wire bonds electricallyconnecting the four conductive balls of the ball grid array to fourcorresponding contacts on the integrated circuit, wherein the first andsecond conductive channels of the Z-directed component are electricallyconnected to a common ground path of the printed circuit board, thethird conductive channel of the Z-directed component is electricallyconnected to a first voltage supply path of the printed circuit boardand the fourth conductive channel of the Z-directed component iselectrically connected to a second voltage supply path of the printedcircuit board, wherein a first of the four contacts on the integratedcircuit electrically connected to the first conductive channel ispositioned next to a third of the four contacts electrically connectedto the third conductive channel and a second of the four contactselectrically connected to the second conductive channel is positionednext to a fourth of the four contacts electrically connected to thefourth conductive channel.
 2. The printed circuit board of claim 1,wherein the four contacts on the integrated circuit are aligned in a rowaccording to one of: (1) the third and fourth contacts being positionednext to each other between the first and second contacts and (2) thefirst and second contacts being positioned next to each other betweenthe third and fourth contacts.
 3. The printed circuit board of claim 1,wherein the first voltage supply path and the second voltage supply pathare configured to transmit a common voltage.
 4. The printed circuitboard of claim 1, wherein the Z-directed component is mounted flush withthe surface of the printed circuit board.
 5. The printed circuit boardof claim 1, further comprising four conductive ball pads eachelectrically connected to a corresponding one of the four conductivechannels of the Z-directed component, wherein each of the fourconductive balls of the ball grid array is positioned on andelectrically connected to a corresponding one of the four conductiveball pads electrically connecting the conductive channels of theZ-directed component to the conductive balls of the ball grid array. 6.The printed circuit board of claim 5, wherein at least one of theconductive ball pads is positioned on top of the Z-directed component.7. The printed circuit board of claim 6, wherein the at least oneconductive ball pad overlaps the Z-directed component and the surface ofthe printed circuit board.
 8. The printed circuit board of claim 6,wherein the entire at least one conductive ball pad is positioned on topof the Z-directed component.
 9. The printed circuit board of claim 5,wherein at least one of the conductive ball pads is positioned on thesurface of the printed circuit board and connected to the correspondingconductive channel of the Z-directed component by a trace across thesurface of the printed circuit board.
 10. A printed circuit board,comprising: a Z-directed capacitor mounted in a mounting hole in theprinted circuit board, the Z-directed capacitor including: a body havinga top surface, a bottom surface and a side surface, the body including aplurality of stacked layers composed of a dielectric material and havinga conductive material plated on a surface thereof; four conductivechannels extending through a portion of the body along the length of thebody, the four conductive channels being selectively connected to theconductive material plated on the surface of the stacked layers; and anintegrated circuit mounted on a surface of the printed circuit board,the integrated circuit having a ball grid array that includes fourconductive balls each being electrically connected to a correspondingone of the four conductive channels of the Z-directed component, theintegrated circuit having a core region having a first voltage supplypath and a ground path and an input/output region having a secondvoltage supply path and the ground path, the second voltage supply pathbeing configured to transmit a voltage different from a voltagetransmitted by the first voltage supply path, wherein a first and asecond of the four conductive channels of the Z-directed component areelectrically connected to the ground path, a third of the fourconductive channels of the Z-directed component is electricallyconnected to the first voltage supply path and a fourth of the fourconductive channels of the Z-directed component is electricallyconnected to the second voltage supply path.
 11. The printed circuitboard of claim 10, wherein a first set of the stacked layers areelectrically connected to the first and second conductive channels and asecond set of the stacked layers are electrically connected to the thirdand fourth conductive channels, the first and second sets of stackedlayers being arranged in an alternating pattern, the first and secondconductive channels being electrically connected to each other by theconductive material plated on the surface of the first set of stackedlayers, and the third and fourth conductive channels being eachelectrically connected to a respective portion of the conductivematerial plated on the surface of the second set of stacked layers, saidrespective portions of conductive material of the surface of the secondset of stacked layers being separated from each other.
 12. The printedcircuit board of claim 10, wherein the four conductive channels of theZ-directed component are each side channels in the side surface of thebody.
 13. The printed circuit board of claim 10, wherein the fourconductive channels each extend through an interior portion of the bodyspaced inward from the side surface of the body.
 14. The printed circuitboard of claim 10, wherein the body of the Z-directed component has acylindrical cross-sectional shape and the four conductive channels arespaced about 90 degrees from each other around the perimeter of thebody.